sh: Support for extended ASIDs on PTEAEX-capable SH-X3 cores.

This adds support for extended ASIDs (up to 16-bits) on newer SH-X3 cores
that implement the PTAEX register and respective functionality. Presently
only the 65nm SH7786 (90nm only supports legacy 8-bit ASIDs).

The main change is in how the PTE is written out when loading the entry
in to the TLB, as well as in how the TLB entry is selectively flushed.

While SH-X2 extended mode splits out the memory-mapped U and I-TLB data
arrays for extra bits, extended ASID mode splits out the address arrays.
While we don't use the memory-mapped data array access, the address
array accesses are necessary for selective TLB flushes, so these are
implemented newly and replace the generic SH-4 implementation.

With this, TLB flushes in switch_mm() are almost non-existent on newer
parts.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/sh/include/asm/cpu-features.h b/arch/sh/include/asm/cpu-features.h
index 86308aa39731..694abe490edb 100644
--- a/arch/sh/include/asm/cpu-features.h
+++ b/arch/sh/include/asm/cpu-features.h
@@ -21,5 +21,6 @@
 #define CPU_HAS_LLSC            0x0040  /* movli.l/movco.l */
 #define CPU_HAS_L2_CACHE        0x0080  /* Secondary cache / URAM */
 #define CPU_HAS_OP32            0x0100  /* 32-bit instruction support */
+#define CPU_HAS_PTEAEX          0x0200  /* PTE ASID Extension support */
 
 #endif /* __ASM_SH_CPU_FEATURES_H */